Oil heater



y May 19, 1931. c. R. WAGNER v 5 OIL HEATER Filed July 21, 1930 no@ a-oo o Cary Alwugrller dauw,

Patented May 19, 1931 UNITED STATES PATENT oFFlcE C ABY R. WAGNER, OFCHICAGO, ILLINOIS, ASSIGNOR T GYRO PROCESS COMPANY, 0F DETROIT,MICHIGAN, A. CORPORATION OF MICHIGAN OIL HEATER Application led July 21,

This invention relates to improvements in oil heating stills orconverters, and an outstanding object of the invention resides in theformation of the heat reflecting walls of 5 the furnace of the still orconverter to procure a more effective distribution or concentration ofthe radiant heat developed within the furnace so that such heat may bedirected to greater advantage on the tubes or elements through which ispassed the oil or oil vapors for heat treatment, whereby such oil or oilvapors will be subjected to temperatures to produce optimum conversionconditions.

In the conversion or molecular decomposi- '1'5 tion of petroleum oils attemperatures in excess of substantially 1000 F., it is necessary toquickly and almost instantly raise the temperature of such oil or oilvapors as the latter enter the initial pass or bank of heating tubesfrom approximately 750 to 1000o F. for the purpose of securinge'iiicient cracking of the oil and also for the purpose of eliminatingor minimizing the liberation of free carbon within said tubes orelements. It has been found that free carbon is released copiously invapor phase systems of oil conversion vwhen the oil is within atemperature range of between 600 and 1000 F. and, therefore, in order toheat the oil rapidly to conversion temperatures in excess of 1000 F.asvquickly as it enters the tubes or elements of a still or converter,the present invention comprehends the design of the walls of the furnaceor other heater so that the radiant heat developed in the furnace willbe directed toward and concentrated on the entrance portions of said.oil circulating tubes. This serves the purpose of effecting the desiredrapid raise in temperature of the oil from sub-conversion to conversiontemperatures.

Since radiant heat is absorbed from ten to fifteen times faster thanconvected heat, I

have discovered that by curving the walls of the furnace in relation toa focal position defined by the source of heat, the desired direction ofpropagation of the radiant heat with respect to t-he heating tubes orelements is obtainable, with the result that said radiant heat isreflected, so that by directing this heat upon theinitial pass ofconverter 1930. Serial No.' 469,402.

tubes the resultant rapid rise the temperature of the oil va ors undertreatment is Referring more particularly to the draw-v ings the numeral1 designates an oil heater or furnace in its entirety. The specific typeof heater illustra-ted is that type commonly known as a tube still andconsists of a setting formed from lire brick or other heat resistingmaterial. Preferably, the setting comprises a bottom wall 2, front andback walls 3 and '4 respectively, longitudinally extending transverselyspaced parallel side walls 5 5 and a top or crown wall 6. Within thesetting there is arranged a transversely extending bridge wall 7, theupper end of which terminates below and in spaced relation from the topor crown wall 6. The bridge wall serves to divide the setting intoburner and tube compartments 8 and 9 respectively. Ar-

ranged within the burner compartment is one vor more groups of oilburners 10 which in operation comprise the heat source.

Disposed horizontally within the tube compartments 9 are oil conveyingtubes or elements 11. The upper or inlet pass of these tubes isdesignated by the letter A. Oil or vapor enters this upper pass of tubesat one' end thereof and after passing or .circulating through the tubesin the bank A, such oil or oil vaporis transferred to the nextsucceeding lower bank of tubes by means of return bends or headers 12and the circulation of the oil then continues in a like manner throughthe succeeding lower passes or banks of tubes,

until the o il or oil vapors have reached the desired temperature andthe desired reactions have taken place wherein what is known as thecrackin of the oil is effected. Cracking, as is well nown, is the termemployed to designate the molecular decomposition of' o ils having ahigher boiling point into oils of lower boiling point. Thus in the vaporphase methods of oil conversion, to which the present heater isparticularly adapted, o ils or oil vapor are introduced into the initialpass A o f the tube bank at a temperature of approximately 75()o F. andafter being subjected to the heat of the furnace, the oils in Vaporousform leave the outlet or lower pass of tubes at a temperature of, forexample 115()o F. The velocity and temperature of the oil vapors beingdetermining factors in the rate of conversion.

As previously stated, we have discovered that in the operation of asystem of this character it is necessary in the procuring of the bestconversion conditions and in minimizing the deposition of free carbon inthe tubes of the converter, to secure a rapid and approximatelyinstantaneous rise in the temperature of the oil vapors as soon as thelatter enter the first pass of tubes. The principles underlying thisprocess have been set forth in the eo-pending application filed jointlyby C. R. Wagner, R. Stahl and J. B. Weaver, Ser. No. 196,884, filingdate J une '6, 1927, now U. S. Patent 1,763,609. In the design of apractical commercial structure for carrying out this process the furnaceor heater shown herein has the bottom of the burner compartment 8 curvedto produce a substantially parabolical reflecting surface 13 the burners10 being disposed in what may be termed the focal center of thissurface. The surface 13 is prefer ably formed from a smooth vitrifiedmaterial of high heat resisting properties such as carborundum orsilica, and the relation an d form of the surface 13 with respect to theburners 10 are such as to reflect the heat upwardly in substantiallystraight parallel lines as indicated at B upon the crown or roof surface15 of the burner compartment.

This roof surface is also of peculiar conguration and, as shown inFigure 1, the said roof surface is curved longitudinally to produce asemi-parabola curve as at C. This curve is so shaped that the radiantheat striking the same is reflected, as indicated at D, upon all of thetubes disposed in the upper tube bank A, or, in other words, the rays Dare distributed throughout the length of the tube compartment 9. Inaddition to the longitudinal curvature of the roof surface 15, thelatter is transversely curved, as shown in Figure 2, so that the radiantheat developed Within the burner compartment instead of being uniformlydistributed upon each of the tubes in the pass A throughout the fulllength of such tubes, such radiant heat will bel directed orconcentrated upon the entrance portion of the tube A for a distance ofsub-' stantially one-third of their length. The transverse curvature ofthe roof surface 15 is such as to secure this distribution of theradiant heat for the purposes specified, the letter E being employed todesignate the roof curvature when viewed in transverse section as shownin Figure 2.

By constructing the furnace so that the radiant heat will beconcentrated upon the entrance portion of the initial tube bank thedesired rapid elevation in the temperature of the oil vapors enteringthe converter is secured with the result that the converter may bemaintained in continuous operation for extended periods of time withoutrequiring frequent shut-downs to remove clogging carbon deposits whichwould otherwise be presv ent if the temperature of the oil vapors werenot controlled as set forth. It will be understood that all of the heatreflecting surfaces are rendered as smooth as practicable and are formedfrom refractory materials having heat resisting properties sufficient topermit of the employment of the high furnace temperatures and in thisconnection I have found carborundum or silica sufficient to meetpractical requirements.

l/Vhat is claimed is:

1. In an oil heater, avwall structure formed to comprise side, front,back, bottom and top Walls' composed of refractory materials anddefining an enclosed heating space, a bridge wall extending transverselyof said space and having the upper edge thereof terminated below saidtop wall, the bridge wall serving to divide the heater into burner andtube compartments, burner means disposed in said burner compartment,stationary relatively horizontally extending rows of oil heating tubesmounted in connection with the walls of said tube compartment, thebottom of said burner compartment being substantially of parabolicalform to reflect heat rays from said burner means substantiallyvertically upward upon the top wall of the heater, said top wall beingcurved longitudinally of said burner compartment to reflect heat raysincident thereon substantially downwardly and angularly upon all of thetubes comprising the upper row of tubes disposed in said tubecompartment, and said top wall being additionally curved transversely ofthe heater to reflect said heat rays incident thereon in a concentratedmanner upon the oil entrance portions of the tubes comprising said upperrow.

2. In an oil heater, a furnace comprising a setting formed to include atransversely ex tending bridge wall which divides the setting internallyinto burner and tube compartments, burners disposed within said burnercompartment, a bank of horizontally arranged tubes in said tubecompartment, and a top wall 'provided in connection with said settingand arranged over said burner compartment and tube compartment, said topwall over` said burner compartment being longitudinally curved toreflect radiant heat upon the tubes comprising the upper row of the tubebank, and said top wall being additionally curved transversely toreflect such radiant heat upon the oil inlet portions of said upper rowof tubes.

3. In an oil heater, a furnace setting formed to include an internallysituated bridge wall which divides the setting internally into burnerand tube compartments, a burner situated within said burner compartmentsand a plurality of horizontally arranged tubes disposed in rows orpasses Within said tube compartments, the walls of said burnercompartments being curved to concentrate through reflection the radiantheat developed Within said burner compartment upon the oil inlet ends ofthe tubes comprising the upper pass in said tube compartment.

4. In an oil heater, a furnace setting comprising bottom, front, back,side and top walls, a transversely extending bridge wall situated withinsaid setting and having its upper end terminated below said top wall,said bridge wall serving to define within said setting a burnercompartment and atube compartment, a burnerdisposed within said burnercompartment, and a pluralityv of horizontally arranged rows or passes oftubes situated within said tube compartment, said top wall being curvedlongitudinally and transversely to concentrate the radiant heatdeveloped within the furnace upon the entrance portion of the upper passof tubes situated within said tube compartment.

5. In an oil heater, a furnace setting formed to include spaced burnerand tube compartments, said compartments being separated by atransversely extending bridge wall, a burner situated within said burnercompartment, the bottom of said burner compartment being of parabolaform to refleet heat rays upwardly upon the top wall of said furnacesetting, said top wall over said burner compartment being curvedlongitudinally to reflect the heat rays directed thereon downwardly andangularly upon the upper pass of tubes in the tube compartment, and saidtop wall being curved transversely to direct the heat rays upon certainof the ends of the tubes comprising said upper pass, in order that thedeveloped radiant heat within said furnace will be concentrated upon theentrance portions of said tube bank to effect a more rapid heating ofthe oil passing through this portion of the tube bank than in theremaining portions thereof.

In testimony whereof I affix my signature.

' CARY R. WAGNER.

